Systems and methods for process scale isolation of immunoglobulin G

A method for isolating a target protein from a solution comprising the target protein and a plurality of contaminants, comprising:

• adding a salt to the solution to generate a supernatant and a precipitate;
• dissolving the precipitate in an aqueous solution to generate a dissolved precipitate comprising the target protein and a first portion of the plurality of contaminants;
• applying the dissolved precipitate to a first ion exchange media having a first charge with a first polarity under first buffer conditions selected to not bind the target protein to generate a first bound fraction comprising a second portion of the plurality of contaminants and a first flow-through, wherein the first flow-through comprises the target protein and a third portion of the plurality of contaminants;
• preparing a second ion exchange media selected to bind both the target protein and a fourth portion of the plurality of contaminants under second buffer conditions, wherein the second ion exchange media comprises a second charge with a second polarity that is opposite that of the first polarity;
• applying the first flow-through to the second ion exchange media under second buffer conditions to generate a second bound fraction comprising the fourth portion of the plurality of contaminants and a second flow-through comprising the target protein;
• wherein preparing comprises selecting a limited capacity of the second exchange media such that greater than 70% of content of the target protein in the solution is recovered in the second flow-through.